26 Oct
2004
26 Oct
'04
3:39 a.m.
Good report, thanks for all the info.
Joel White <cv223(a)comcast.net> writes:
With 2.6.9 - In Duplex mode, xruns occur at a rate of
scores per min
of recording on *either* drive. Kernel latency trace indicates that
the max kernel latencies were around 200 - 400 usec. Xruns are
eliminated when Jack is set to Capture only.
3. It seems that there is some kind of interaction
between Ardour,
the kernel, and the disk system. The fact that xrun behavior is so
different between the two kernels (xruns on the IDE drive with 2.6.9,
but not 2.4.23) suggests something is up with the kernel. The
latency_trace on 2.6.9 does not report that the kernel latency is the
problem, but it is clearly something going on with this kernel. It is
certainly possible that I have something misconfigured (Lee Revell
checked out my .config, so at least that seems ok). I can send more
info to anyone who may be able to help.
I recently built 2.6.9 to test the latest realtime-lsm LKML patch.
The patch worked, but realtime performance was horrible on my system,
especially compared to 2.6.8.1. I ran JACK in Duplex mode with ardour
and jamin. Next, I built 2.6.9-mm1, and things are working pretty
well.
So, despite not having done a careful test like yours, I think there
is a latency problem with 2.6.9. I'd be very interested to see what
happens if you run your test on 2.6.9-mm1. The kernel developers
probably would, too.
--
joq